By default, ESXi generates a single path between the software iSCSI adapter and the iSCSI targets, unless the iSCSI array is a multi-portal array allowing target access via more than one network interface. To enable load balancing or redundancy for iSCSI traffic egressing an ESXi host, you will need to bind multiple VMkernel interfaces (vmk) to the software iSCSI adapter. There is an important catch to this type of configuration though, that is that the Vmkernel interfaces and the iSCSI target portals cannot be on disparate network subnets. In other words, they should be in the same broadcast domain (VLAN). This does not mean that iSCSI does not support routing; it is only a limitation with the port binding.
Port binding is only done with the software iSCSI adapter and dependent hardware iSCSI adapters.
